1. Field of the Invention
The embodiments of the invention provide a device, method, etc. for a sandwiched organic land grid array (LGA) structure.
2. Description of the Related Art
LGA organic packages undergo tremendous stresses exerted upon the module via the LGA retention schemes. Currently, the cinch LGA contact system is actuated at an average force of approximately 85 grams per contact. There are attempts to reduce this force to the 40 to 65 gram range. For a 1657 input/output (I/O) module at 65 grams, the clamping force is 237 pounds of clamping force. These stresses can cause warping and cracks in the organic substrate, resulting in decreased reliability. The embodiments of the invention provide a structure to disperse the stresses, thus reducing the possibility for inducing reliability related defects.
Current industry standard solutions for managing the stresses basically center around a peripheral stiffener ring, or metal back plates places on the other side of the board to help prevent warping. Both of these solutions are expensive, difficult to assemble, limit in their success to manage the stresses, or require a larger substrate due to depopulated contacts under the device die.
Furthermore, 3-D chip/die stacking is a technology in electronic packaging that optimizes printed wiring real estate, minimizes enclosure volume above low height modules, and minimizes data bus lengths. 3-D chip/module stacking is known in the art, however current 3-D module assembly techniques require the soldering of each module/die layer to the other or stacking of die then wire bonding between die and substrate. This joining complicates assembly issues: known good die/module methodology is required and expensive; solder hierarchy is complicated and expensive; and, rework is not always possible. These problems drive module cost higher and higher.
3-D chip/die stacking is an up and coming technology in the packaging world today. Current techniques for assembly require the “layers” of the stack be soldered to the previous layers.
A strict assembly hierarchy needs to be followed, mostly to preserve previous solder connections, and this solder hierarchy is expensive. In addition, the solder joints have reliability issues.